Circuit breaker



J. C. DALEY CIRCUIT BREAKER ;'Feb. 13, 1934.

Filed July 2. 1930 w w m fl my Patented Feb. 13, 1934 v UNITED STATES PATENT OFFICE CIRCUIT BREAKER James C. Daley, Chicago, Ill., assignor to Jcfierson Electric Company, Chicago, 111., a corporation of Illinois My invention relates to a circuit breaker, particularly for use with gaseous tube sign circuits, oil burner ignition circuits and the like, and contemplates the use of a bi-metallic strip as the circuit control, and the use of the heat of the arc in the high voltage circuit for breaking the supply circuit when the voltage rises to an excessive amount.

My invention is illustrated in the accompanying drawing, in which:

Figure 1 is a circuit diagram of a gaseous tube sign circuit embodying the present invention;

Figure 2 is a circuit diagram of an oil burner ignition circuit embodying the invention;

Figure 8 is a plan view of the base and top or cover of the preferred constructional embodiment of my improved circuit breaker; and

Figure 4 is an end view showing the base and cover in assembled relation.

Referring first to Figure 1, a neon or other gaseous tube, or equivalent device, is indicated at 5, and is connected across the secondary side 6 of a transformer 7. The secondary winding is shown as being sectionalized or composed of a pair of secondary windings 8, 8 grounded centrally or intermediate the secondary windings 8, 8 at 9.

The primary side 10 of the transformer is connected to the alternating current supply line 11,

which may be at 110 volts, or any other suitable the supply circuit. When the arm 12 is in the position shown in full lines, the contact 15 contacts the contact 16 and the supply circuit is closed from one side of the line through the contacts 15, 16, arm 12 and primary 10 to the other side of the line.

The circuit breaker proper of my present invention comprises a bi-metallic strip or arm 18, fixedly anchored at one end at 19, grounded at 20 and with its opposite end, which is movable with temperature changes under the bi-metallic action, normally engaged with the free end of the arm 12, endwise, as shown, and holding said arm 12 in full line position with the contact 15 in contact with the contact 16. An insulating block 18a a contact 16 fixedly supported and connected into with a contact 23 which is adjacent to the bimetallic arm 18 intermediate its length. An air gap is thus interposed between the lead 22 and the ground and is of such length as to effectively prevent flow of current at normal voltages.

Obviously, with the bi-metalllc arm 18 and the i arm 12 in the positionlshown in full lines with the contact 15 in contact with the contact 16, the supply line 11 is closed, the supply line circuit 11 being as above pointed out, and the secondary or high voltage circuit is from one side of the secondary through the gaseous tube, or equivalent devices 5, to the other side of the secondary 6.

In the particular embodiment illustrated the ground 9 is substantially mid point of the windings 8, 8 so that with an induced voltage of 15000 volts, for example, in the complete secondary the voltage above ground on a short circuit is limited to the voltage in one side of the secondary. As is well understood in the art, the voltage under load, that is when the tube 5 is in operation, is considerably lower than the voltage existing under open circuit conditions brought about, for example, by failure of the tube 5. Therefore, on open circuit the voltage in the secondary circuit will be increased to full open circuit voltage which will 88 cause an are at gap 23, the heat of which will flex the bi-metallic arm. This movement will break contact 15-16 opening the primary circuit of the transformer by separating the contacts 15 and 16 and preventing injury to the tube, trans- 90 former and high tension side.

Upon the occurrence of an open circuit in the secondary the heat in the arc will bow the bi- .metallic-arm 18 to the position shown in dotted lines at 14, this bowing or deflection of the bimetallic arm 18 freeing the arm 12 and permitting separation of the contact 15 carried thereby from the contact 16 and thereby breaking the supply line 11 by the use of a bi-metallic arm and by the heat of the arc in the secondary. After the line is opened in this manner the open circuit or other condition may be relieved and the bimetallic strip 18. will cool and return to its full line position so that all that is necessary is to see to it that this bi-metallic strip is engaged endwise with the arm 12 to hold the contact 15 in contact with the contact 16, as shown in full lines.

In Figure 2 the secondary side of the transformer '1' is indicated at 6', and the primary side 10' of the transformer is connected to the alternating current supply line 11, which may be at 110 volts, or any other suitable voltage. The secondary circuit has a spark gap 5' for the oil burner ignition. I find that with the present invention this gap may be of the order of threesixteenths of an inch, although the particular size of the gap may, of course, vary.

As before, the secondary circuit has a lead 22 connected electrically with one side and provided with a contact 23, which normally is spaced from the bi-metallic arm 18 at a point intermediate its length a distance slightly in excess of the gap 5. The bi-metallic strip or arm 18 is fixedly anchored at one end at 18' and is grounded at 20'. Its opposite end, which is, as in the preceding embodiment, movable with temperature changes under the bi-metallic action, and is provided with an insulating block 18b which is normally engaged with the free end of the arm' 12, endwise, as shown, and holds the arm 12' in full line position with the contact 15' in contact 'with the contact 16'. The alternating current supply line is indicated at 11 and may be at 110 volts, or any other suitable voltage. As before, the arm 12' is biased to open position indicated in dotted lines at 14' and is released to open to' bi-metallic arm will cool and return to its full line position so that all that is necessary is to see to it that this bi-metallic strip 18 is engaged endwise with the arm 12 to hold the contact 15 in contact with the contact 16 as shown in full Referring now to Figure 3 wherein I have shown one preferred specific construction embodying my invention, the reference numeral 20 indicates the base formed of porcelain or other non-conducting material and upon which the arms 12 and 14 are mounted. The arm 12 is anchored, as at 13, to a bracket 21 fixedly mounted on the base by means of a bolt 22. On the underside of the base 20 and electrically connected to the bolt 22, and hence to the bracket 21 and arm 12, is an electric conductor in the form of a strip 24 which is connected to a terminal bolt 25 which is adapted to be connected to one end of the primary side 10 of the transformer 7. The arm 12 is provided with a contact 15, as shown in Figure 1, which is adapted to make electric connection with the contact 16. The latter contact is fixedly carried upon a bracket 26 secured to the base 20 by means of a second terminal bolt 28. The terminal bolt 28 is adapted to be connected to one side of the source of supply 11.

The bi-metallic element 18 is shown in Figure 3 as secured to a bracket 30 which is also mounted on the base 20 by means of a terminal bolt 31 which is adapted to be connected to ground 20 as shown in Figure l. The cover 34 is provided with an arm 35 having a pointed end 36 which, when the cover is in place on the base 20, is adapted to be spaced from the bi-metallic arm 18 a short distance forming the air gap 23 referred to above and indicated diagrammatically in Figure 1. In order to bring the arm 35 in proper position relative to the bi-,metallic arm 18, the arm 35 is provided with an offset portion, as indicated by the reference numeral 38. The arm 35 is secured to the cover and electrically connected to a terminal bolt 39 by. which connection is made to the lead 22 shown in Figure 1. The cover is provided with the openings 41, 42 and 43 adapted, respectively, to be received over the terminal bolts 25, 28 and 31. These terminal bolts furnish a convenient means for securing the cover in position, as well as affording connecting means for the arms 12 and 18 and associated structure. 3

The block of insulating material 25 is secured to the bi-metallic arm 18 in any desired manner and serves the purpose, as pointed out above, of preventing any electrical contact between the arm 12 and the arm 18. While I have shown the insulating block 25 mounted on and movable with the bi-metallic arm 18, it is to be understood that this insulating block may be mounted on the end of the arm 12 instead of on the arm 18. It is therefore to be understood that such construction comes within the scope of my present invention.

The base 20 may be provided with a raised portion 48 on which .the parts are mounted, and which affords a convenient means for positioning the cover 34 in proper place on the base 20. Preferably opposite corners of the raised portion 48 are cut away and the cover 34 formed in a corresponding manner to afford an opportunity to secure the base 20 to a panel or the like by screws or other means passing through openings '50 formed in the corners adjacent the cut away portions of the raised part 48 of the base.

Figure 3 shows the arms 12 and 18 in full lines in a position which corresponds to their position just after the primary circuit is opened by the bi-metallic arm 18 flexing due to the heat of the are at 23 away from the end of the arm 12. Under normal operating conditions it is desirable to provide some means for restoring the arms to operative position, that is, with the contacts 15 and 16 closed. To this end I have provided a lever 50, preferably of fiber or other non-conducting material, and pivotally mount the same in such a position as to be capable of moving the arm 12 to close the circuit at the contacts 15 and 16. One convenient means for pivotally mounting the arm 15 is shown in Figure 3 where this arm is provided with an aperture and is received by the bolt 22. The cover 34 is provided with a notch 51 to which the handle portion 52 of the lever 50 may extend. A nut 54 threaded onto the bolt 22 effectively holds the arm or lever 50 in proper position.

In order to restore the arms to operating position all that it is necessary to do is to swing the arm or lever 50 in a clockwise direction, pressing the arm 12 against its natural resiliency, thus closing the circuit through the contacts 15 and 16 and allowing the bi-metallic arm 18 to spring downwardly behind the extreme end of the arm 12 to hold the latter in operating position. The insulating block 45 effectively prevents any flow of current from one arm to the other.

While I have shown and described the preferred embodiment of my invention, it is to be understood that my invention is not to be limited to the specific structure shown and described, but that, in fact, widely different means may be employed in the practice of the broader aspects of my invention.

What I claim, therefore, and desire to secure by Letters Patent is:

1. In an automatic circuit breaker, in combination, a stationary contact member, a movable contact member adapted to contact with said stationary contact member and tending to move out of contact with said stationary contact member, a thermostatic element adapted to be positioned to hold said movable contact member in contact with said stationary contact member, and a spark terminal spaced from said thermostatic element and forming a spark gap therebetween.

2. In an automatic circuit breaker, in combination, a stationary contact member, a movable contact member adapted to contact with said stationary contact member and tending to move out of contact with said stationary contact member, a thermostatic element adapted to be positioned and having an insulating element for engaging said movable contact member to hold the same in contact with said stationary contact member,"

and a spark terminal spaced from said thermostatic element and forming a spark gap therebetween.

3. In an automatic circuit breaker, in combination, a stationary contact member, a movable contact member adapted to contact with said stationary contact member and tending to move out of contact with said stationary contact member, a thermostatic element adapted to be positioned to hold said movable contact member in contact with said stationary contact member, a spark terminal spaced from said thermostatic element and forming a spark gap therebetween, and means for moving said movable contact member into contact with said stationary contact member.

4. In an automatic circuit breaker, in combination, a stationary contact member, a spring contact arm anchored at one end, the opposite end of said contact arm adapted to contact with said stationary contact member and tending to move out of contact with said stationary contact mem ber, a thermostatic strip having an insulating element adapted for engaging the free end of the spring contact arm endwise of the thermostatic strip to hold the spring contact arm in contact with the stationary contact member, and a circuit including a spark terminal spaced from said thermostatic strip and forming a spark gap therebetween for heating the thermostatic strip to flex the same to position releasing said spring contact arm upon a rise in voltage in the circuit including said spark gap.

5. In an automatic circuit breaker, in combination, aninsulating base, a stationary contact member mounted on said base, a movable contact member mounted on said base, said movable contact member being adapted to contact with said stationary contact member and tending to move out of contact with said stationary contact member, a thermostatic element mounted on said base and adapted to be positioned to hold the movable contact member in contact with said stationary contact member, a cover for said base, and a spark terminal carried by said cover and upon positioning said cover on said base spaced from said thermostatic element to'form a spark gap therebetween.

6. In an automatic circuit breaker, in combination, an insulating base, a stationary contact member mounted on said base, a movable contact member mounted on said base, said movable contact member being adapted to contact with said stationary contact member and tending to move out of contact with said stationary contact member, a thermostatic element mounted on said base and adapted to be positioned to hold the movable contact member in contact with said stationary contact member, a cover for said base, a spark terminal carried by said cover and upon positioning the cover on said base spaced from said thermostatic element to form a spark gap therebetween, and an arm pivoted to said base and accessible externally of the base and cover for moving the movable contact member into contact with said stationary contact member.

JAMES C. DALEY. 

